One quick trip to the recent past of the internet via the wonderfully time-wasting WayBackMachine is enough to remind us of all of the "creative" uses of font manipulation in what passed for information design. Who knew that these skills would one day come in handy?
According to a recent study, non-standard and varied type fonts can create "desirable difficulties" and create additional cognitive loads that tend to improve learning. The results seem counter intuitive. Most instructors strive to create easy-to-receive lessons, and students perceive that a lesson is successful if they feel they have had a relatively easy time learning the material.
However, disfluency--"the subjective, metacognitive experience of difficulty associated with cognitive tasks"--has, in some cases, been shown to direct students to "process information more deeply, more abstractly, more carefully, and yield better comprehension." One key mechanism in these results seems to be the idea that disfluency (say, difficult to read type faces) cues a learner to be less confident that they have actually learned what they just read. As a result, there is a greater chance that they might engage the material with greater effort and in a more complex fashion. In their study, "Fortune favors the bold and the italicized: Effects of disfluency on educational outcomes," Diemand-Yauman, Oppenheimer, & Vaughan conclude that "Student retention of material across a wide range of subjects (science and humanities classes) and difficulty levels (regular, Honors and Advanced Placement) can be significantly improved in naturalistic settings by presenting reading material in a format that is slightly hard to read."
See: Diemand-Yauman, C., Oppenheimer, D. M., & Vaughan, E. B. (Forthcoming). Fortune favors the bold and the italicized: Effects of disfluency on educational outcomes. Cognition.